Question

Which of the following is not equivalent to $p\to q$.

• A. $p$ only if $q$
• B. $q$ is necessary for $p$
• C. $q$ only if $p$
• D. $p$ is sufficient for $q$

Answer 1

Answer: (C)

$p\to q$ means,
(i) $p$ is sufficient for $q$
(ii) $p$ only if $q$
(iii) $q$ is necessary condition for $p$
(iv) $\sim q\to \sim p$